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Wx::PaintEvent

A paint event is sent when a window’s contents needs to be repainted.

Derived from

Event

Object

Event table macros

To process a paint event, use this event handler macro to direct input to a member function that takes a PaintEvent argument.

evt_paint() { | event | ... } Process a EVT_PAINT event.

See also

Event handling overview

Remarks

Note that In a paint event handler, the application must always create a PaintDC object, even if you do not use it. Otherwise, under MS Windows, refreshing for this and other windows will go wrong.

For example:

void MyWindow::OnPaint(PaintEvent& event)
{
    PaintDC dc(this);
}
DrawMyDocument(dc);

You can optimize painting by retrieving the rectangles that have been damaged and only repainting these. The rectangles are in terms of the client area, and are unscrolled, so you will need to do some calculations using the current view position to obtain logical, scrolled units.

Here is an example of using the RegionIterator class:

// Called when window needs to be repainted.
void MyWindow::OnPaint(PaintEvent& event)
{
  PaintDC dc(this);
}
// Find Out where the window is scrolled to
int vbX,vbY;                     // Top left corner of client
GetViewStart(&vbX,&vbY);
int vX,vY,vW,vH;                 // Dimensions of client area in pixels
RegionIterator upd(GetUpdateRegion()); // get the update rect list
while (upd)
{
  vX = upd.GetX();
  vY = upd.GetY();
  vW = upd.GetW();
  vH = upd.GetH();
}
// Alternatively we can do this:
// Rect rect(upd.GetRect());
// Repaint this rectangle
...some code...
upd ++ ;

Methods

PaintEvent.new

PaintEvent.new(Integer id = 0)

Constructor.

[This page automatically generated from the Textile source at Wed Sep 09 02:21:18 +0100 2009]